// allocation.
	if newsize < fixedStack {
		return
	}
	// Compute how much of the stack is currently in use and only
	// shrink the stack if gp is using less than a quarter of its
	// current stack. The currently used stack includes everything
	// down to the SP plus the stack guard space that ensures
	// there's room for nosplit functions.
	avail := gp.stack.hi - gp.stack.lo

}

type g struct {
	// Stack parameters.
	// stack describes the actual stack memory: [stack.lo, stack.hi).
	// stackguard0 is the stack pointer compared in the Go stack growth prologue.
	// It is stack.lo+StackGuard normally, but can be StackPreempt to trigger a preemption.
	// stackguard1 is the stack pointer compared in the //go:systemstack stack growth prologue.
	// It is stack.lo+StackGuard on g0 and gsignal stacks.

	//
	// For cdecl and stdcall, all arguments are on the stack.
	//
	// For fastcall, the trampoline spills register arguments to
	// the reserved spill slots below the stack arguments,
	// resulting in a layout equivalent to stdcall.
	//
	// For arm, the trampoline stores the register arguments just
	// below the stack arguments, so again we can treat it as one
	// big stack arguments frame.
	args unsafe.Pointer

//
// nosplit because it's called on the syscall path when stack movement is forbidden.
//
//go:nosplit
func (tl traceLocker) ok() bool {
	return tl.gen != 0
}

// traceRelease indicates that this M is done writing trace events.
//
// nosplit because it's called on the syscall path when stack movement is forbidden.
//
//go:nosplit
func traceRelease(tl traceLocker) {

	// freed.
	HeapObjects uint64

	// Stack memory statistics.
	//
	// Stacks are not considered part of the heap, but the runtime
	// can reuse a span of heap memory for stack memory, and
	// vice-versa.

	// StackInuse is bytes in stack spans.
	//
	// In-use stack spans have at least one stack in them. These
	// spans can only be used for other stacks of the same size.
	//

}

var profileDescriptions = map[string]string{
	"allocs":       "A sampling of all past memory allocations",
	"block":        "Stack traces that led to blocking on synchronization primitives",
	"cmdline":      "The command line invocation of the current program",
	"goroutine":    "Stack traces of all current goroutines. Use debug=2 as a query parameter to export in the same format as an unrecovered panic.",

		// timestamp, M, P, G, stack. However, after they get turned into Event,
		// they have the arguments stack, M, P, G.
		//
		// In Go 1.21, CPU samples did not have Ms.
		mappedArgs = timedEventArgs{uint64(ev.StkID), ^uint64(0), uint64(ev.P), ev.G}
	default:
		return Event{}, fmt.Errorf("unexpected event type %v", ev.Type)
	}

	if oldtrace.EventDescriptions[ev.Type].Stack {

	return p.list
}

func (ps *parseState) emph(dst, src []Inline) []Inline {
	const chars = "_*~\"'"
	var stack [len(chars)][]*emphPlain
	stackOf := func(c byte) int {
		return strings.IndexByte(chars, c)
	}

	trimStack := func() {
		for i := range stack {
			stk := &stack[i]
			for len(*stk) > 0 && (*stk)[len(*stk)-1].i >= len(dst) {
				*stk = (*stk)[:len(*stk)-1]
			}
		}
	}

Src:

// spanSetBlockAlloc represents a concurrent pool of spanSetBlocks.
type spanSetBlockAlloc struct {
	stack lfstack
}

// alloc tries to grab a spanSetBlock out of the pool, and if it fails
// persistentallocs a new one and returns it.
func (p *spanSetBlockAlloc) alloc() *spanSetBlock {
	if s := (*spanSetBlock)(p.stack.pop()); s != nil {
		return s
	}

			rv = AnyValue(fmt.Errorf("LogValue panicked\n%s", stack(3, 5)))
		}
	}()

	for i := 0; i < maxLogValues; i++ {
		if v.Kind() != KindLogValuer {
			return v
		}
		v = v.LogValuer().LogValue()
	}
	err := fmt.Errorf("LogValue called too many times on Value of type %T", orig.Any())
	return AnyValue(err)
}

func stack(skip, nFrames int) string {
	pcs := make([]uintptr, nFrames+1)